Wired for Management (WfM) Specification Version 2.0, developed by Intel Corporation of Santa Clara, Calif., enables computer systems to be universally managed over networks without sacrificing agility or performance. WfM defines a mechanism called Preboot Execution Environment (PXE) that bypasses the operating system transition in the computer system basic input output system (BIOS) in order to find a server on the network (boot server) to download and execute code, instead of loading the operating system from the boot device on the computer system. Another component of PXE technology makes it possible to configure or reconfigure a computer system remotely, even with a blank hard disk drive. The computer system typically has a universal service agent loaded locally in the BIOS and/or LAN adapter.
This agent enables, for example, the system to interact with a remote server in order to dynamically retrieve the requested boot image across the network, making it possible to install the operating system and user configuration of a new system without a technician present. PXE is tamper-resistant through a Boot Integrity Services (BIS) application program interface (API) that offers security-oriented services for the pre-boot environment. BIS is implemented in the BIOS of the target computer system to verify the integrity of a downloaded to the computer system. If the credentials do not match those previously recorded in non-volatile storage, the new boot image is not executed.
A problem, however, may occur in mobile computer systems (e.g., notebooks), or other power-managed platforms where the computer system may be in a low power sleep state. The problem occurs if the platform wakes up from the low power sleep state and has to re-authenticate the user or platform in BIOS. Similarly, the remote server may need to wake up the computer system to perform management services. Since a user may not be present during the wake-up, the client computer has to authenticate the remote server as though the remote server was the local user and verify what the remote server is authorized to do.
WfM PXE/BIS code does not load or get control until the end of the power on self-test (POST) stage of the boot process. As a result, the computer system often hangs up. Moreover, the problem is exacerbated by the fact that when AT attachment 3 (ATA-3) password enabled hard disk drives lose power during the low power sleep state, or in a C3 state wherein the hard disk drive is asleep. In such a scenario the disk drives do not recall the password that is needed to allow access to media commands.